Sending Javamail in Spring MVC

You never set a From address in your Message so
JavaMail is getting it from the configuration of
your computer, but your computer isn't properly
configured to have a fully qualified domain name,
probably because it's using DHCP to get its IP
address.

Add a call to message.setFrom and it will work
a lot better.

Also, you're using a very old version of
JavaMail, and because of that the debug output you
posted includes your password in a form that
anyone can decode it. You might want to change
your password immediately. And upgrade to a newer version of JavaMail.

I don't think your question made any sense at all. When you're sending
email via SMTP, you have to choose a SMTP host (either an IP address
or a DNS alias name which will then be resolved to an IP address).
Your OS will then pick which network interface to use based on the
configured routing table.
Routing IP address to an interface doesn't sound like an application
layer job at all.

Well after some trial and error it turns out I had too much going on I
guess. Some clarification as to why the above works for new user
registration but not for my new ticket submission would be an even
better answer.
Below is the way I got it to work using ActionMailer. New file
admin_mailer.rb and got rid of after_create and send_ticket_notifier
in ticket.rb
# /mailers/admin_mailer.rb
#######

Actually the RingBufferAsyncTaskExecutor isn't ThreadPoolTaskExecutor,
so you can't use it that way.
You can simply override clientInbound(Outbound)Channel beans from your
AbstractWebSocketMessageBrokerConfigurer impl and just use
@EnableWebSocketMessageBroker:
@Configuration
@EnableWebSocketMessageBroker
@EnableReactor
public class WebSocketConfig extends
AbstractWebSocketMessageBrokerConfigure

You can use AspectJ's ability to declare errors and/or warnings based
on pointcuts.
Disclaimer: I have never used Spring, so I am not an expert there and
just making up an example without much sense for demonstration.
Spring bean with prototype scope:
package de.scrum_master.app;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;
@Component
@